Jig Journal: Arc Drawing Bow

Searching for (and Finding) the Arc of the Competent.
By Robert W. Lang
Pages: 76-78

From the December 2007 issue #166
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When woodworking throws you a curve, how do you respond? It’s easy to become locked into one solution because it’s familiar and miss an easy alternative. This is often the case when a curve is part of a design. Laying out and cutting arcs is a common task, but the best way to do it is a matter of scale. Different tactics are needed for larger or smaller radii.

If the radius of a curve is less than 6″ or so, a compass is the obvious choice. If the radius is known, it’s simply a matter of setting the compass point to the right dimension and swinging the arc. But many times, particularly if you’re creating a new design, you don’t know (and likely don’t care) what the radius is. You want the arc to stop and start at certain points along an edge, and you want the high point to be a certain distance from the edge.

If this is this case, here is a simple way to find the radius you want, using your layout tools to find it. It is easier to do this on a piece of graph paper or a scrap of plywood rather than on an actual workpiece, because the point of the compass will end up off the edge of the piece.

From the December 2007 issue #166
Buy this issue now